Pulsed sources of radiant energy, such as xenon sources, have been used in various types of optical systems. However, the structure and the position of the light source can vary from pulse to pulse thereby resulting in a structured as opposed to a diffused, more uniform, radiant energy signal.
The problem has been recognized and one solution has been previously disclosed in MacDonald U.S. Pat. No. 4,660,984 entitled "Reflectometer Featuring An Integrated Cavity of Enhanced Efficiency", assigned to the Assignee of the present invention. The reflectometer of the MacDonald patent provides mixing of a pulsed radiant energy signal for the purpose of generating a more uniform output signal.
While the structure of the MacDonald patent does provide a uniform radiant energy signal, the disclosed apparatus for achieving that result is relatively expensive. There continues to be a need for radiant energy mixing structures which provide a uniform output radiant energy signal, with minimum losses, using inexpensive components. It would further be desirable if such mixing structures are physically small and light weight so as to be readily usable with a variety of optical systems.